The present invention relates to the field of X-rays and more particularly, to X-ray tubes or X-ray emitters and an X-ray apparatus.
An X-ray tube mounted, for example, in a radiological imaging apparatus, comprises a cathode and an anode, both being enclosed in an evacuated sealed envelope in order to provide electrical insulation between these two electrodes. The cathode produces an electron beam that is received by the anode over a small surface constituting a focus from which the X-rays are emitted. The envelope is generally transparent to X-rays. The X-ray assembly or tube comprising the cathode, the anode and the envelope is in its turn contained in a enclosure which is opaque to X-rays, except for a part located facing the X-ray beam emitted by the anode, which comprises a window made of a material transparent to X-rays. A gap between the transparent envelope and the opaque enclosure is filled by oil providing electrical insulation and cooling the X-ray source.
On application of a high supply voltage by a generator to terminals of the cathode and the anode, a current called the anode current is established in the circuit through the generator that produces the high supply voltage. The anode current passes through a space between the cathode and the anode in the form of an electron beam that bombards the focus.
To obtain a high-energy electron beam, the electrons are accelerated by an intense electric field produced between the cathode and the anode. To this end, the anode is brought to a very high positive potential with respect to the cathode. This potential may exceed 150 kV.
The cathode assembly comprises elements that are at the same voltage as the cathode, in general an arm or a stand supporting the cathode and a central part supporting the arm and in contact with the end of the envelope away from the anode. A plurality of parallel pins passes through the envelope in a sealed manner, and is axially oriented. One of the pins may be coaxial with the rotating shaft of the anode and the others parallel. The pins project into the internal space of the enclosure and are bathed in oil. The pins are connected to a high-voltage supply via a through hole formed in the enclosure and forming the female part of a connection means capable of cooperating with a corresponding part. An X-ray tube is disclosed in FR A 2 809 277.
While the known X-ray tube or X-ray emitter is satisfactory it is still heavy and is relatively bulky.